Liquid detergent compositions comprising enzymes are well known in the art. It is desirable that such compositions should exhibit long term stability with respect to the enzyme. However, it has been observed that in anionic surfactant liquid detergent compositions the stability of enzymes, in particular cellulases is greatly reduced. The incorporation of cellulase enzymes in such compositions is highly desirable. Thus, the storage instability of such compositions represents a problem to the detergent manufacturer.
It is believed that the reason for the cellulase instability in the presence of anionic surfactants lies with the interactions which occur between the anionic surfactant and the three dimensional structure of the cellulase enzyme. This results in the unfolding of the enzyme and a reduction in its activity.
It has also been observed that this problem is more acute in the presence of protease enzyme. It is thought that the unfolded cellulase enzyme is more vulnerable to attack by protease. Thus, the presence of proteases further deactivates the cellulases.
Therefore it is an object of the invention to provide a liquid detergent composition which comprises anionic surfactant and cellulase, which is storage stable.
In response to this object, the present invention proposes to formulate liquid detergent compositions which comprise liquid detergent soluble hydrophobic amines, which may be primary, secondary, or tertiary amines, or quaternary ammonium compounds, as cellulase stabilizing compounds.
An advantage of the present invention is that it is applicable to the protection of any cellulase, and also finds application in the presence of protease.
Amines have been disclosed in the art in liquid detergent compositions.
EP 160 762, EP 137 615 and EP 137 616 disclose liquid detergents which comprise cyclohexylamine. Compositions are exemplified which comprise anionics, protease and amylase, but there is no mention of cellulase. The role of the cyclohexylamine therein is to stabilize the compositions which are in the form of microemulsions.
EP 177 165, discloses detergent compositions which comprise anionics, cellulase and a variety of primary, secondary, and tertiary amines and quaternary ammonium compounds. The primary, secondary and tertiary amines in EP 177 165 all have at least one long alkyl chain. The compositions in the EP 177 165 mandatorily comprise clay. EP 177 165 does not disclose that amines can stabilize cellulases.
EP 11 340 discloses soften through the wash detergent compositions which comprise tertiary amines and clay. The compositions in EP 11 340 comprise no cellulase.
DE 32 07 487, GB 2 094 826, GB 2 095 275 and EP 137 397 disclose compositions which comprise anionics, cellulase, protease and quaternary ammonium compounds. None of these documents disclose that amines can stabilize cellulases.
EP 120 528 discloses compositions comprising anionics, cellulase with other enzymes, as well as tertiary amines. The tertiary amines in EP 120 528 have at least one long alkyl chain. EP 120 528 does not disclose that amines can stabilize cellulases.
EP 26 528 and EP 26 529 disclose compositions comprising anionics and quaternary ammonium compounds. Both EP 26 528 and EP 26 529 do not disclose cellulase.
WO 91/17243 and EP application numbers 91202880.0, 92200101.2 and 91202882.6 disclose Carezyme.RTM., including in liquid detergents. They do not mention amines.